Furnace and stoker therefor



June 18,l 1929. F. c. GREENE FURNACE AND STOKER THEREFOR Filed Feb. 2,192s Q INVENTOR.

f7@ 72)( 676572@ BY end.

Patente'd June 18, 1929.

UNITED STATES PATENT OFFICE.`

FURNACE AND STOKER THEREFOB.

Application inea February 2, 1928. serial No. 251,so2.

The present invention relates, as indi? cated, to a furnace specificallydesigned for use with a reactive stoker of the general type disclosed inmy copending applicatlon Serial No. 246,686. The primary object of theinvention is to eliminate all of the disadvantageous features of theusual type of furnace when used in connection with the reactive stoker,and certain modifications have been made in the Stoker itself to adaptit more specifically for use with the new furnace. To theAaccomplishment of the foregoing and related ends, said invention, then,consists of the means hereinafter fully described and particularlypointed out 1n the claims.

The annexed drawing and the following description set forth in detailcertain mechanism embodying the invention, such disclosed meansconstituting, however, but one of various mechanical forms in which theprinciple of the invention may be used.

In said annexed drawing:

The single figure is a sectional view of the furnace and Stoker.

Referring more particularly to the drawings, the numeral 1 indicates abase plate having an annular upturned rim 2 and aI central raisedplatform 3. Said platform is reinforced by means of ribs 3, or the like,and is provided in its periphery with a plurality of air inlet apertures4. Centrally of the platform 3 there is an upstanding annular'externally threaded flange 5, and the base plate 1 is formed with a lowannular rib 6 adjacent the rim 2. A support 7 having the shape of ahollow truncated cone, has its larger lower end received within theannular rib 6 and is provided with an outstanding flange 8 at its upperThe furnace proper, or fire pot, is formed of two substantiallyhemispherical sections 9 and 10, provided at their large open ends withexternal flanges 11 and 12 respectively, said flanges being grooved toform a channel 13 when the two sections 9 and 10 are brought into matingrelation. External ribs 14 and 15 are formed on the two sections 9 and10 respectively, upon vertical major circles, the ribs 14 being cut offadjacent their 1ower ends to form shoulders 16 adapted to rest upon theflange 8.

The upper open end of the section is formed with a fiange 18 adapted tosupport the flange 19 of a radiator 20. The radiator 20 encloses ahumidifier 2l, the function of which will be hereinafter described.

At one side of the furnace casing 84 there is mounted a bracket 22adapted to form a support for a flange 23 on a hopper 24. One Wall 25 ofsaid hopper is formed to provide a chamber which may be closed by amating member 26 to form a gear case, and laterally extending hubs 27and 28 surround a substantially central aperture in said gear case. Anejector tube 29 'is `sleeved on the hub 27 and extends through anaperture in the opposite wall of the hopper 24, the projecting end ofsaid tube being provided with handles 30. The portion of the tube 29Within the hopper 24 is provided with an aperture 31 for a purpose to behereinafter described. It is to be understood that the tube 29 isrotatable upon its longitudinal axis.

A conveyor tube 32 is sleeved on the hub 28 and extends through anaperture 33 inl the support 7. Said tube 32 is formed with a hopperedaperture 34 in its upper surface within the confines of the support 7and with an aperture 35 in its lower sur-- fac/e adjacent the gear case25-26. Within the conveyor tube 32 there is rotatably mounted a conveyor36 comprising a tube having a gapped helical thread -37 formed thereonor secured thereto. Said tube 36 is keyed to a worm wheel 38 within thegear case 25-26, and said worm wheel is adapted to be driven by a worm39 on the spindle of a motor 40. The upper end of the tube 36 extends`to a point within the hopper 24 and is sharply beveled at 41. Saidbeveled. end 41 is preferably cut to form serrations or teeth 42.Adjacent the lower end of the tube 36 there is carried a pinion 43 for apurpose to be set out later. Said lower end is beveled as at 44 andextends into an inlet conduit 45 giving access to the interior of abasin 46.

Said basin 46 is formed at its upper end to provide a journal for thehub 47 of a rotatable ash pan 48 said hub being non-rotat-` ably engagedabout the base of a muille 49. The ash pan 48 is formed on its undersurface with a series of teeth 50 in mesh with the pinion 43.Immediately surrounding the hub 47, the ash pan 48is formed with aseries of air inlet apertures 51, and a flange 52 in the form of anupstanding frustum of a cone surrounds said series of apertures.

The rounded upper end 53 of the Inutile 49 is flanged for cooperationwith the flange l54 at the upper end of a depending skirtlike hearthmember 55 adapted to be secured thereto by machine screws 56, or thelike. The lower end 57 of said hearth member 55 is flared outwardly andengages smoothly with the internal surface of the aperture in the lowerend 58 of the section 9. Said end 57 is provided with a plurality of airinlet openings 59. A cylindrical shield 60 provided with a series ofopenings 61 adjacent its upper end is clamped at its upper end betweenthe flanges 53 and 54 of the mullle 49 and hearth member 55,respectively, and its lower end 62 is snugly received within the openupper end of the flange 52.

The mulile 49 is provided with an aperture 63 in its lower end, saidlower end being enclosed within the basin 46, andsaid muille' carries asuitably shaped curvediin 64 adjacent said aperture 63. The lower end 65of a. stator 66 is screw-threaded for cooperation with the threads onthe flange 5, and said stator is formed with a bore 67 registering withthe aperture 68 in the base 3 surrounded by said llange 5. A helicalthread 69 is formed on the external surface of said stator 66, saidthread being so proportioned as to engage snugly the internal walls ofthe mullle 49. The upper end of the stator is flared and is formed ofintegral staggered sections 70 and 71 separated from the body of thestator and from each other to provide outlet openings 72 and 73therebetween. The open upper end of the stator is adapted to besubstantially closed by a cover member 74 spaced slightly from thesection 71 to provide outlet o enings 75.

he urnace is provided with a kindling .door 76 which ispreferably formedhalf in the section 9 and half in the section 10. This method of formingthe door 76 is preferable because of the fact that, when the door is soformed, the two sections 9 and 10 may be ldentical save for the cuttingolf of the ribs 14 to provide the shoulders 16. An ash ejector 77comprising a rod having a hooked low er end 78 extends through thesupport 7 and has it-s end 78 lying upon the upper surface of the ashpan 48. The opposite end of the ejector 77 is pivoted to a link 79,which in turn, is pivoted to a bracket 80 secured to the member 26. Adraft door 81 is provided on the support 7, and said door is preferablyformed with apertures 82 to provide for a desired minimum draft when thedoor 81 is closed.

In operation, the hopper 24 which, of course, may be of any desiredpractical size, is filled with coal. Preferably this coal should be ofthe type known as slack, since slack coal contains few large pieces andmay be handled more easily through the conveyor 36 and in the Inutile49. If the motor 40 is now energized, the conveyor 36 will be rotatedthrough the worm wheel 38. lVith the ejector tube 29 in the positionshown in the drawing, the coal will fall through the aperture 31 intocontact with the upper beveled end I41 of the conveyor 36. This beveledend 41 will agitate the coal and bite7 into the mass of coal to causethe fuel to fall into the conveyor 36. Any large lumps of coal will bechewed up into small bits by the teeth'42, and any large lumps of hardmaterial will be rejected by the open end of the conveyor and leftwithin the tube 29. The coal which falls into the tube 36 Will betumbled about by the rotation of said tube and will fall by gravitythrough the length of the tube and into the basin 46. The beveled end 44of the tube will push the coal downwardly into the basin after the samehas left the tube 36. Coaction of the pinion 43 with the teeth 50 of theash pan 48 will cause rotation of said ash pan and, as the hub 47 of thelatter is nonrotatably secured to the inuHle 49, the inutile willlikewise be rotated. The fin 64, in its rotation, will scoop the coal inthe basin 46 y through the aperture 63 and into the space definedbetween the muille 49 and the stator 66. The interior surface of theinutile 49 is opening in the support, and one portion of such air willfollow a path through the apertures 51, the space between the shield 60and the mulile 49, the apertures 61, the space between the shield 60 andthe hearth member 55, andthe apertures 59 into the fire pot. It will-readily be seen that this stream of air insulates, to some extent, thespace within the mule 49 from the heat in the fire pot, and that the airstream itself will be preheated in its passage along the above describedpath. The coal in its passage upwardly along the thread 69 is preheatedin the manner described in my copending application, Serial No. 246,686,filed January 14, 1928, to the desired temperature as described in saidcopending application. As the coal emerges from the top of the muflle,it enters suddenly into a region of high teinperature, and vapors andgases deficient in oxygen are evolved therefrom. The remaining portionof the air which enters through the draft door in the support 7 willflow through the apertures 4, the aperture 68, the

bore 67, and the apertures 72,7 3, and 75, to come into immediatecontact with these gases and vapors, and the high temperature in thisportion of the furnace will cause combustion of said gases and vapors.Obviously, this second stream of air will be heated in its passage upthe stator bore 67. The element 21 may be used as a humidifierpreferably, or as so much increased radiator surface. Owing to thecombustion having fully occurred below the radiator section, the usuallarge space of the radiator required to finish the combustion of longaming fuels may be diminished to advantage by increasing the radiatorsurface.

It will be seen that the combustion takes place within this furnace intwo distinct parts, one part being combustion of the socalled volatileportion of the coal in the upper part of the fire ot adjacent the airdischarge openings 72, 3, and 75, and the other part beingthe combustionof the socalled fixed carbon part of the coal completed adjacent thebottom of the fire pot. Each of these parts has its own suitable airsupply, the first being delivered through said discharge openings, andthe second bein delivered through the apertures 59. It w1ll be seen,then, that the furnace required is far different from the usual standardtype of furnace wherein the attempt is made to burn the volatile andfixed carbon parts of the fuel within substantially the same space andusually with a single primary air supply and an entirely inadequatesecondary air supply which is too cold to react with the relatively coldvolatiles evolved.

According to the, present invention, two primary'air supplies arepresent. The usual method of burning coal might be considered analogousto an attempt to burn an intimate mixture of gasoline and heavy fuel oilthrough the agency of a carburetor.` It is true that a compromise may bemade in the air mixture so that an optimum result of combustion occurs,but this optimum is not of the highest efficiency where it is attemptedto burn the volatile and fixed carbon parts of carbonaceous fuel withintimacy. The present furnace has been devised to cooperate with thereactive stoker to obtain the greatest possible efficiency ofcombustion, andthe furnace is so designed as to fit and develop theadvantages of this stoker.

When a shovel full of coal is cast into an ordinary furnace, there isthrown in the equivalent of the whole range of combustibles fromgasoline to amorphous carbon. The ignition temperature of the former isvery low, while that of the latter is about as high as is possessed byany combustible material. In between are all sorts of combustibleshaving graduated ignition points. Therefore, with a single air supply,the combustion can,J be only a `compromise. The

lighter constituents, of the fuel ignite first, i

but even though the overdraft is opened, the

constituents have cooled; the air is. cooled;l

bustion reaction are hot when brought into contact. With a fire in thefirepot, the coal which is delivered to the fire pot through the mufile49 is hot.` The volatiles which leave the coal at the discharge mouth ofthe muffle are hot. The air which meets such volatiles, being dischargedfrom the apertures 72 73, and 75, is hot, having been preheated in itspassage through the stator bore 67. Immediately smokeless combustion ofthe volatiles ensues upon the contact of said air with such volatiles.When the volatiles are thus consumed at the top of the mufiie, theremaining carbon drops into the fire pot Where the temperature is veryhigh. Here it is brought into contact with hot air, such air having beenpreheated in its passage through the apertures 51, the space between theshield 6() and the muifle 49, the apertures 61, the space between theshield 60 and the hearth member 55, and the apertures 59. The combustionof the carbon is, therefore, complete. lThese reactions take place atthe highest efficiency because of the particular design of the furnaceherein disclosed, the dimensions and proportions of said furnace havingbeen specifically designed to cooperate with the Stoker to attain thishigh efficiency.

As the fuel is burned within the fire pot, the ashes will fall throughthe apertures 59 onto the ash pan 48 and be carried around4 into contactwith the hooked end 78 of the ash ejector 77. Said ejector may beactuated to drag the ashes from the ash pan and cause them to fallthrough the hoppered aperture 34 and into the `interior of the conveyortube 32, where the ashes are picked up by the thread 37 and carried tothe upper- Vend of said tube where they fall through. the aperture 35into the ash container 85.

The material rejected by the bevelled end 41`of the conveyor 36 will beretained in the ejector tube 29 until such time as an operator rotatessaid tube to brin the aperture 31 into a lower position, uch materialwill then fall into the bottom of the hopper, whence it may be removedthrough the door 83.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein dlsclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as myinvention 1. A furnace comprising a base plate, a support formed as atruncated cone provided with an external annular flange at its upperend, said support being mounted on said base plate, a substantiallyhemispherical fire pot section having circumferential ribs formedthereon, said ribs providing shoulders adapted to rest on said flange, asecond mating substantially hemispherical section superimposed on saidfirst section and secured thereto, a radiator mounted on the open upperend of said second section, a conical member in said radiator having itsapex directed downwardly, and a furnacel casing secured to said baseplate and enclosing all of said parts.

2. The combination with a reactive stoker of a furnace enclosing saidStoker, said furnace being generally spherical i-n contour andopening atits top into a radiator mounted thereon, and a conical member having itsapex directed downwardly in said radiator immediately overlying saidstoker.

3. The con'xbination with a reactive stoker mounted on a base plate, ofa furnace resttop of said section, a conical humidifier having its apexdirected downwardly within said radiator arid immediately overlying saidstoker, and a support for saidfurnace engaging `shoulders on said firstsection formed by cutting off` saidribs.

5. In a heating unit, a base plate, an annular support mounted on saidbase plate for supporting a furnace, a furnace comprising a pair ofmating, substantially hemispherical sections, one superimposed upon theother, ribs formed externally of said sections and extending uponvertical circumferences of said furnace,'the ribs of the lower of saidsections being cut away to form shoulders adapted to rest upon saidsupport, and a reactive stoker mounted on said base plate and extendinginto said furnace, said stoker including a rotatable ash pan adaptedsubstantially to close the open lower end of said lower section.

6. In combination with a reactive Stoker in which fuel is adapted to bepreheated to a desired degree during its slow progress upward through atubular member and discharged into a fire pot at a. point above thelevel of the fire bed therein in a highly reactivated state, a furnacecomprising a pair of mating substantially hemispherical members adaptedsubstantially to enclose such lStoker and to form a fire pot, theuppermost of said members being formed with an open top lyingsubstantially in a horizontal plane with the points of upper airdischarge of such stoker, a radiator superimposed on .said uppermostmember' and presenting a relatively large surface, and means to prevententrance of air to said fire pot save through channels in the' passagethrough which the entering air will be preheated to a high degree.

Signed by me, this 30th day of January,

FRANK C. GREENE.

